We use should and ought to when we want to give people advice, or show that we think something is the right thing to do in the present and the future. Using the negative form shows that we think something is the wrong thing to do.
The opposite is should not (shouldn’t) and ought not to.
- a)You should get more sleep. The less tired you are, the happier you will be.
- b)You ought not to drink so much alcohol. It is bad for your health.
To talk about past behaviour, we use sb + should + have + past participle + ob, or ought to + have + past participle.
- c)He should not have told her what I said. It was a secret.
- d)They ought not to have sold the house without telling him first.
To express an idea of permission, we use may, could and can. Long ago, we only used may to ask for permission, but nowadays we use can and could too.
We tend to say can with the subject I, and could with the subjects you, we, they, he, she and it, because using the past form of can, could, is politer than using the present form.
- e)May I use your bathroom please?
- f)Could you help me with this for a minute?
- g)Can I go home early please? I am really tired.
- h)CouldI leave early today please? (politer)
To talk about permission in the past, we don’t usually use a modal verb. Instead, we use was/were allowed to.The exception is when you use reported speech.
- i)We were allowed to stay until late.
- j)They said we couldstay until late.
Exercise 1.- Grammar
Choose the correct option for each sentence. Both may be possible.
- a)People should/ ought to be polite at all times.
- b)People shouldn’t/ ought to not test medicine on animals.
- c)Drivers should to have/should have passed their driving test before they drive without an instructor.
- d) I ought to have not/I ought notto have been so rude to her. After all, she is the Queen!
- e)Can/May I borrow your car please?
- f)Can/Could you help me with my homework please?
- g)My father said I can/could invite all my friends to our house to watch the football.
- h)When I was a child, I could/was allowed to stay up late on a Friday night.